With a continuous scaling down of a field-effect transistor feature size, a working speed thereof is faster and faster. However, a feature size of the field-effect transistor has reached a physical limit thereof, and therefore it will become more and more difficult to improve the working speed of the field-effect transistor by reducing the feature size thereof. Therefore, there is a need for other methods for improving the speed of a device, for example, Ge or a SiGe material with high Ge content is used as a channel material to increase a mobility of carriers. However, because the Ge or the SiGe material with high Ge content is unstable at high temperature and doping elements such as As, P and B in a Ge layer or a SiGe layer with high Ge content are very difficult to be activated, how to form an activated heavily-doped source and/or drain in the Ge layer or the SiGe layer with high Ge content has become a focus.